In perhaps his biggest win yet, Sanders took 50.1 percent of the vote, while Democratic frontrunner Hillary Clinton, who was expected to take the Rust Belt state by double digits, received 48 percent (at the time of publication), according to the New York Times.

Sanders' performance was a major upset for the Clinton campaign, whose victory in Michigan was expected to deliver a blow to Sanders' chances for the presidency — given that many of the issues on which the Sanders campaign hinges resonate strongly with voters in the industrial state.

"We are in the midst of a very tight race," a somewhat baffled Sanders said in an impromptu speech in Florida before the results were called.

BREAKING: Bernie elected Camp President, now addressing campers from the main cabin on ongoing Color War dispute pic.twitter.com/uDjhveapO6

"What tonight means it that the Bernie Sanders campaign, the people’s revolution that we are talking about, is strong in every part of the country and frankly we believe that our strongest areas are yet to happen,” he said.

The win marks a milestone for Sanders, and breathes fresh air into his presidential campaign. Michigan, where Clinton had led the polls in the run up to Tuesday's vote, is a hotbed for issues like "unfair" trade agreements, a "rigged economy," and income inequality — all issues championed by Sanders in a Democratic debate on Sunday night in the city of Flint. The state also contains a large population of Black voters, who have largely been thought to support Clinton, however, it is too soon to know if Black voters propelled sanders to victory.

Michigan is by far the most heavily African-American state Sanders has won. (14% of total pop, at least double any other state he's won.)